Pharmacokinetic Properties of Intravenous Ibuprofen in Healthy Chinese Volunteers

Comparison of intravenous ibuprofen pharmacokinetics between Caucasian and Chinese populations using physiologically based pharmacokinetics modeling and simulation

BACKGROUND

Intravenous ibuprofen, a nonsteroidal anti-inflammatory drug, is widely used as an antipyretic and analgesic in adults and children. This study was designed to evaluate ethnic differences by comparing the pharmacokinetics of intravenous ibuprofen in Caucasian and Chinese populations using physiologically based pharmacokinetics (PBPK) modeling and simulation.

METHODS

A PBPK model for intravenous ibuprofen was developed in adults and children utilizing the Simcyp Simulator. The model was tested and verified against published literature and unpublished data obtained from the Caucasian adult population, Caucasian pediatric population and Chinese adult population.

RESULTS

The developed PBPK model could adequately pilot the pharmacokinetics of intravenous ibuprofen, and the major observed values were within the 90% prediction interval in both adults and children. Both folding errors of the maximum peak concentration (Cmax) and area under the concentration-time curve (AUC) were 1.5-fold less in the Caucasian and Chinese populations. In addition, no significant differences in weight-normalized Cmax and AUC were observed between the Caucasian and Chinese adult populations. Moreover, there were no obvious pharmacokinetic differences between the Caucasian and Chinese pediatric populations with intravenous infusion (10 minutes) of 10 mg/kg by age group.

CONCLUSION

This study indicates that the pharmacokinetic profile and the parameters of intravenous ibuprofen are analogous in Caucasian and Chinese populations, either adults or children. In addition, this study provides effective evidence that the dosing scheme of intravenous ibuprofen in Chinese children can remain the same as the regimen that the original company (Caldolor®) provided.

Antinociception produced by nonsteroidal anti-inflammatory drugs in female vs male rats

The primary aim of this study was to examine sex differences in acute antinociceptive and anti-inflammatory effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in rats. Complete Freund's adjuvant (CFA) was administered to adult Sprague-Dawley rats to induce pain and inflammation in one hindpaw; 2.5 h later, vehicle or a single dose of the NSAIDs ibuprofen (1.0-32 mg/kg) or ketoprofen (0.1-10 mg/kg), or the COX-2-preferring inhibitor celecoxib (1.0-10 mg/kg) was injected i.p. Mechanical allodynia, heat hyperalgesia, biased weight-bearing, and hindpaw thickness were assessed 0.5-24 h after drug injection. Ibuprofen and ketoprofen were more potent or efficacious in females than males in reducing mechanical allodynia and increasing weight-bearing on the CFA-injected paw, and celecoxib was longer-acting in females than males on these endpoints. In contrast, ketoprofen and celecoxib were more potent or efficacious in males than females in reducing hindpaw edema. When administered 3 days rather than 2.5 h after CFA, ketoprofen (3.2-32 mg/kg) was minimally effective in attenuating mechanical allodynia and heat hyperalgesia, and did not restore weight-bearing or significantly decrease hindpaw edema, with no sex differences in any effect. Neither celecoxib nor ketoprofen effects were significantly attenuated by cannabinoid receptor 1 or 2 (CB1 or CB2) antagonists in either sex. These results suggest that common NSAIDs administered shortly after induction of inflammation are more effective in females than males in regard to their antinociceptive effects, whereas their anti-inflammatory effects tend to favor males; effect sizes indicate that sex differences in NSAID effect may be functionally important in some cases.

A target concentration strategy to determine ibuprofen dosing in children

BACKGROUND

Ibuprofen is widely used for ductus arteriosus closure in premature neonates and for analgesia in children and adults. There are no maturation descriptors of clearance. This lack of maturation understanding limits dosing recommendations from premature neonates to adulthood.

METHODS

Published clearance estimates from different aged patients determined after administration from time-concentration profiles were used to construct a maturation model based on size and age. Curve fitting was performed using nonlinear mixed-effects models. A target concentration strategy was used to estimate maintenance dose at different ages.

RESULTS

There were three publications reporting an estimate of individual clearance estimates in premature neonates, three reporting population clearances in infants, 11 in children 2-15 years (1 with individual and 9 with population clearances), and 13 adult studies (1 with individual and 12 with population clearances). Clearance maturation, standardized to a 70 kg person was described using the Hill equation. Mature clearance was 3.81 (CV 15.5%, 95%CI 3.72, 3.92) L/h/70 kg. The maturation half-time was 36.8 (CV 9.2%, 95%CI 34.7, 40.9) weeks postmenstrual age and the Hill coefficient 11.5 (95%CI 8.1, 15). A target effect of four units (visual analogue scale 0-10) correlated with an effect site concentration of 6.3 mg/L: a concentration achieved at trough after 400 mg 8 hourly in adults.

CONCLUSION

Previously published pharmacokinetic parameters can be used to develop maturation models that address gaps in current knowledge regarding the influence of age on a drug's disposition. Maturation of ibuprofen clearance was rapid and was 90% of adult values by the first month of life in term neonates (ie, 44 weeks postmenstrual age) and 98% of standardized adult estimates by 3 months of age (53 weeks postmenstrual age). Clearance informed dosing predictions in all ages (premature neonate to adult) and matched those doses in common use in children older than 3 months.

Pharmacokinetics of dimemorfan phosphate tablets in healthy Chinese volunteers

OBJECTIVE

Investigate the pharmacokinetic properties of the antitussive dimemorfan phosphate tablets in healthy male and female Chinese volunteers after single and multiple-dose administration; and to evaluate the food-effect on pharmacokinetics of dimemorfan.

METHODS

12 subjects received a single dose of 10 mg and 40 mg dimemorfan phosphate tablets, respectively in study stage 1. Another 12 subjects received a single dose of 20 mg dimemorfan phosphate tablets under fed conditions, a single dose of 20 mg dimemorfan phosphate tablets under fasting conditions and multiple-dosing of 20 mg dimemorfan phosphate tablets 3 times per day, respectively in study stage 2. The washout between each treatment was 1 week. Plasma dimemorfan was quantified by a high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method.

RESULTS

After single-dosing of 10 mg, 20 mg and 40 mg dimemorfan phosphate tablets, C_max, AUC_0-t and AUC_0-∞ were dose proportional, which achievd 6.19 ± 7.61 ng·mL^-1, 101 ± 171 and 117 ± 210 ng·mL^-1·h, respectively after single-dosing of 40 mg dimemorfan phosphate tablets. T_max ranged from 2.75 to 3.96 h and t_1/2 ranged from 10.6 to 11.4 h. After multiple-dosing of 20 mg dimemorfan phosphate tablets, the Accumulation Index (AI) was 2.65 ± 1.11. The pharmacokinetic parameters after single-dosing of 20 mg dimemorfan phosphate tablets under fed conditions were similar with those under fasting conditions. Sex did not affect the pharmacokinetics of dimemorfan phosphate tablets.

CONCLUSIONS

Single-dosing of dimemorfan phosphate tablets exhibited linear kinetic characteristics. Multiple-dosing of 20 mg dimemorfan phosphate tablets 3 times per day caused obvious accumulation. No food effect or sex effect on the pharmacokinetics of dimemorfan phosphate tablets was observed. Chictr.org identifier: ChiCTR-ONC-14004851.